The present invention relates to the field of golf club putters. More particularly, the present invention relates to a design for a golf club putter in which the golfer can effectively strike the ball holding the shaft in any position from substantially vertical to an incline of at least 10 degrees with respect to vertical, and provides the golfer with symmetry and balance in the putter when using an upright style of putting stroke.
Two authors have estimated that putting comprises 43% of the game of golf ("Putt Like the Pros", by Dave Pelz and Nicholas Mastroni, Harper & Row, 1989, page 4). Therefore, considerable effort has been expended on analysis of putting and ways to improve a golfer's score by more accurate putts.
Putting a ball into the cup involves essentially two distinct steps. In the first step, the golfer must choose the path of the ball over the green from its present position into the cup. The second step has the golfer striking the ball in such a way as to cause it to follow the planned trajectory into the cup. Both steps are very complicated.
In choosing the path of the ball over the putting surface into the cup (that is, the "line" of the putt), the contour of the green is the first consideration for many golfers. The overall contour determines the curvature of the golf ball as it approaches the cup (that is, the "break" of the putt). In addition, the friction of the ball with the green (the "speed" of the green) must be considered in determining the correct speed for the putt. Obviously, the ball must reach the cup to have any chance of going in. But balls moving too rapidly also cause problems. A ball approaching the cup at too high a speed can strike the rim of the cup and be deflected away from the hole, whereas a slower-moving golf ball will not ricochet as much from the rim of the cup and probably fall into the hole. Also, putts travelling too fast will result in a longer return putt to the hole in the event of a miss. The speed of the green is determined by such factors as the length and type of grass, the natural slant of grass growth (the "grain" of the green), the moisture content of the grass and soil, and occasionally in competition, even by wind conditions.
All the above factors affecting the speed of the green are to be considered in addition to the uphill and downhill rolling of the putt following the overall undulations of the green itself. Further complicating matters is the fact that the curvature in the path of the rolling golf ball ("break") is itself determined in part by the speed at which the ball is rolling. Thus, it is quite possible for a ball rolling too quickly to fail to follow the contour of the green as expected by the golfer, tending to prefer a trajectory closer to a straight line in accordance with Newton's laws. This results in "hitting through the break", and a missed putt. Thus, the complex art of putting is further complicated by the fact that the correct line for the putt is not entirely separate from speed of the ball as determined by the way it is struck. The many factors of putting are interrelated and affect the trajectory of the putt in a complex way.
Once the golfer has determined the line of the putt (including consideration of the speed), the next problem is to strike the ball so as to cause it to follow this line. Pelz and Mastroni (cited above) report in their Chapter 5 on controlled experiments in rolling golf balls towards a hole in which essentially all variables in starting the golf ball on its way have been eliminated through careful engineering. Even under these near-ideal conditions, many putts are missed. The authors conclude that even extremely well-groomed greens are subject to small variations in surface structure (spike marks, imperfectly repaired ball marks, small variations in sod contours, etc.) making the trajectory of a golf ball subject to random disturbances beyond the control of even the most dedicated student of putting. Thus, making 100% of one's putts is not possible on real greens, even in theory. However, the quest of many golfers is to make all the putts they reasonably can. This leads at once to the problems of striking the ball in such a way as to start it properly on the desired path.
The human golfer is subject to many imperfections in his or her putting stroke. Numerous books (including that cited above) attempt to describe many of these putting problems and suggest solutions. Of course, the major problem is not simply an imperfect stroke for which compensation may be possible. The major concern is the variation of the putting stroke from shot to shot, leading to unpredictable putting results. The elimination of shot to shot variation is thus a major concern of golfers.
Two basic approaches are taken in a golfer's attempt to bring predictability and reproducibility into his or her putting stroke. First, lessons and practice to train the body are employed, attempting thereby to condition the muscles to act in coordination the same way from stroke to stroke. Secondly, golfers frequently choose equipment which minimizes or reduces the adverse consequences of their particular putting problem. The thrust of the present invention is towards a new style of putter offering advantages and flexibility for the individual golfer in selecting his or her most advantageous putting stroke.
There are essentially two considerations in selecting equipment for the game of golf (in this case, a putter). The particular piece of equipment must be suitable for the golfer, feel comfortable to him or her, and provide a modicum of advantage as perceived by the golfer over other choices of equipment. Secondly, for many golfers it is necessary that the equipment meet the requirements of the U.S. Golf Association (or another recognized rule-making body) and, therefore, be acceptable for use in private or tournament competition, be acceptable in determining recognized handicaps, and avoid unfair advantages for a particular golfer. The official rules of golf change from time to time, often in response to technical advances in equipment. Therefore, one cannot predict 100% reliably whether a new club will be "conforming", in the absence of an official determination by the appropriate ruling body. However, it is one intent of the inventor that the putter of the present invention is apparently in conformity with the rules of golf as commonly understood and applied by golfers in the United States of America. If, however, the club of the present invention is found to lack conformity with the rules of golf, or the rules are specifically altered to make this club nonconforming, the utility and novelty of the present invention will in no way be affected for those many golfers who simply wish to enjoy the game on their own terms.
In selecting suitable golf equipment, many factors are taken into consideration by the individual golfer. For the case of putters, the golfer considers the balance of the club in his or her hand; the weight of the clubhead and its distribution; the structure of the club in terms of ease of alignment, sighting marks, shape, color, etc., and the size and location of the "sweet spot" (that is, the region on the clubhead wherein the golf ball may be struck without causing serious rotation of the clubface during impact and resulting misdirection of the putt). Many types of clubs have been developed to address in various ways some or all of these factors. Full consideration of these is beyond the scope of our present discussion and not required for a complete understanding of the present invention.
An important factor not typically addressed by present putters is the angle made by the shaft with the putting surface in the region of the ball. Typically, in addressing the ball for a putt using a conventional putter, the clubface is held near the ground and aligned with the ball for putting. When held in this position by the golfer, the club shaft typically makes a certain and fixed angle with the local plane of the green. If the golfer attempts to strike the ball holding the shaft at a different angle from that for which the putter was constructed, the clubface strikes the ball at an incline, typically adversely affecting the dynamics of the club-ball impact. Using conventional putters, it is important for the golfer to select a putter for which this angle of shaft and green is comfortable for him or her as there is typically no variation possible to account for local variations in the angle of the green, or in the preferences of the particular golfer. The present invention provides a single putter in which the ball may be struck effectively with the shaft in any position from vertical to an angle at least 10 degrees from vertical.
The present putter utilizes a curved clubface which allows the ball to be struck with the shaft held at any angle desired by the golfer from true vertical to at least 10 degree deviation from vertical. No matter which angle the golfer chooses to hold the shaft in striking the ball, effectively equivalent striking areas and geometries of clubface make impact with the golf ball. This should be contrasted with the invention of Guendling (U.S. Pat. No. 4,523,758) in which an angled clubface is employed. When used in a vertical position as suggested by Guendling, the golf ball is struck by the apex of a "V". When held at the appropriate angle from vertical (as determined by the angle of the "V"), the golf ball is struck by a substantially flat clubface. When held at an intermediate angles, the golf ball is struck by an inclined clubface. The present putter eliminates this variation in the impact zone of ball and clubface by the use of a curved and balanced clubhead as described fully below.
The structure of the present putter should also be contrasted with that of Bernhardt (U.S. Pat. No. 4,163,554). Bernhardt suggests using a modified two-handed croquet-style putting stroke, putting the ball from a position next to the golfer while the golfer faces along the direction of the putt. The putter proposed by Bernhardt has a substantially flat portion along the bottom of the striking face and has a shaft emanating from the putting head at an angle. The putter of the present invention can also be used in such an upright style, forward-facing putting stroke. However, the centrally located shaft of the present club (combined with the curved bottom of the striking face) allows the golfer using the putter of the present invention to employ a truly vertical putting motion in striking the putt.
The club of the present invention, with its combination of vertical shaft, curved clubhead, and symmetrical structure, allows many different putting strokes to be used with the same club. The present club can accept a short shaft, thereby permitting the golfer to use the one-handed putting stroke suggested by Guendling. The use of the present putter with a longer shaft allows one to use a conventional putting stroke. An even longer shaft on the present club allows the golfer to use the forward-facing upright style of stroke suggested by Bernhardt. Alternatively, as described fully below, the use of a longer shaft on the present club allows the golfer to employ an upright style of stroke while facing the golf ball in a conventional putting address position.